Photosensitive element having substantially flat interface between electrode and photosensitive layer and manufacturing method thereof

ABSTRACT

A photosensitive element and a manufacturing method thereof are provided. The manufacturing method of the photosensitive element includes successively depositing a second conductive layer, a photosensitive material layer, and a first top electrode material layer on a substrate; forming a first patterned photoresist layer on the first top electrode material layer; patterning the first top electrode material layer by using the first patterned photoresist layer as a mask to form a first top electrode; removing the first patterned photoresist layer; patterning the photosensitive material layer by using the first top electrode as a mask to form a photosensitive layer; forming an insulation layer having an opening on the first top electrode; and forming a second top electrode on the insulation layer, and the second top electrode is electrically connected to the first top electrode via the opening.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 107118347, filed on May 29, 2018. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to an electronic element and a manufacturingmethod thereof, and more particularly, to a photosensitive element and amanufacturing method thereof.

Description of Related Art

With the advancement in technology, the functions of personal electronicequipment are becoming more diverse. For instance, in addition to thephone function, current hand phones on the market often further containfunctions frequently used in everyday life such as camera, video, note,internet, and etc. In these multifunction electronic equipment, aphotosensitive element is often provided. The photosensitive element candetect an ambient light of an electronic product, and in addition tohelping the user obtain better camera and video quality, somephotosensitive elements can further detect fluctuations on the fingersurface of a user such that the electronic product has the function offingerprint recognition. How to increase the imaging quality of thephotosensitive element to accurately recognize the fingerprint of a useris an urgent issue of various industries.

SUMMARY OF THE INVENTION

The invention provides a manufacturing method of a photosensitiveelement that can solve the issue of poor imaging caused by damage to aninterface of a photosensitive layer.

The invention provides a photosensitive element that can solve the issueof poor imaging caused by damage to an interface of a photosensitivelayer.

A manufacturing method of a photosensitive element of the inventionincludes the following. A second conductive layer, a photosensitivematerial layer, and a first top electrode material layer aresuccessively deposited on a substrate. Next, a first patternedphotoresist layer is formed on the first top electrode material layer,and the first top electrode material layer is patterned by using thefirst patterned photoresist layer as a mask to form a first topelectrode. Next, the first patterned photoresist layer is removed andthe photosensitive material layer is patterned by using the first topelectrode as mask to form a photosensitive layer. Next, an insulationlayer is formed on the first top electrode. The insulation layer has anopening. Next, a second top electrode is formed on the insulation layer,and the second top electrode is electrically connected to the first topelectrode via the opening.

A photosensitive element of the invention includes a bottom electrode, aphotosensitive layer, a first top electrode, an insulation layer, and asecond top electrode. The bottom electrode, the photosensitive layer,and the first top electrode are stacked on a substrate in order. Thematerial of the photosensitive layer includes a silicon-rich oxide. Thebottom electrode and the photosensitive layer have a substantially flatinterface therebetween. The insulation layer is disposed on the firsttop electrode. The insulation layer covers the first top electrode, thephotosensitive layer, and the bottom electrode. The insulation layer hasan opening. The second top electrode is electrically connected to thefirst top electrode via the opening.

Based on the above, the photosensitive element and the manufacturingmethod thereof can alleviate the issue of poor imaging of thephotosensitive element to increase display quality.

In order to make the aforementioned features and advantages of thedisclosure more comprehensible, embodiments accompanied with figures aredescribed in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1A to FIG. 1O are manufacturing process schematics of aphotosensitive element according to an embodiment of the invention.

FIG. 2 is a top view of some elements of a photosensitive elementaccording to an embodiment of the invention.

FIG. 3 is a cross section of a photosensitive element according toanother embodiment of the invention.

FIG. 4 is a top view of some elements of a photosensitive elementaccording to another embodiment of the invention.

FIG. 5 is a cross section of a photosensitive element shown according tosection line B-B′ of FIG. 4.

DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As those skilled in the art would realize,the described embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present invention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms such as those defined in commonly useddictionaries should be interpreted as having a meaning that isconsistent with their meaning in the context of the related art and thepresent invention and will not be interpreted as idealized or excessive.The formal meaning, unless explicitly defined in this article.

Exemplary embodiments are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments. Thus, variations in the shapes of theillustrations as a result, for example, of manufacturing techniquesand/or tolerances are contemplated. Thus, embodiments described hereinshould not be construed as limited to the particular shapes of regionsas illustrated herein but are to include deviations in shapes thatresult, for example, from manufacturing. For example, a regionillustrated or described as flat may, typically, have rough and/ornonlinear features. In addition, the acute angle shown can be round.Thus, the regions illustrated in the figures are schematic in nature andtheir shapes are not intended to illustrate the precise shape of aregion and are not intended to limit the scope of the claims.

FIG. 1A to FIG. 1O are manufacturing process schematics of aphotosensitive element according to an embodiment of the invention. FIG.2 is a top view of some elements of a photosensitive element accordingto an embodiment of the invention. FIG. 1O corresponds to the locationof section line A-A′ of FIG. 2, and FIG. 2 omits some components in FIG.1O.

Referring to FIG. 1A, a substrate SB is provided, and a patterned firstconductive layer M1 is formed on the substrate SB. The substrate SB is,for instance, a rigid substrate or a flexible substrate. For instance,the material of the substrate SB can be glass, plastic, compositematerial, or other materials that can provide support and can be usedfor the manufacturing of a plate structure.

The patterned first conductive layer M1 includes a gate G and acapacitor electrode CE. The gate G is electrically connected to a scanline. The capacitor electrode CE is located between two adjacent scanlines. The material of the patterned first conductive layer M1 is aconductive material. For instance, the material of the patterned firstconductive layer M1 can be a single- or multi-layer stacked metalmaterial, such as at least one selected from the group consisting ofcopper (Cu), molybdenum (Mo), titanium (Ti), aluminum (Al), tungsten(W), silver (Ag), gold (Au), and an alloy thereof. The patterned firstconductive layer M1 can be manufactured by patterning a metal materialvia a lithography process, but is not limited thereto.

Referring to FIG. 1B, a gate insulation layer GI is formed on thesubstrate SB and the patterned first conductive layer M1. The patternedfirst conductive layer M1 is located between the substrate SB and thegate insulation layer GI. The gate insulation layer GI can be acomposite structure of a single-layer structure or multi-layerstructure, and the material of the gate insulation layer GI is, forinstance, silicon nitride, silicon oxide, silicon oxynitride, othersuitable dielectric materials, or a combination of the above.

Referring to FIG. 1B, after the gate insulation layer GI is formed, asemiconductor pattern layer SM is formed on the gate insulation layerGI. The semiconductor pattern layer SM is overlapped with the gate G.The semiconductor pattern layer SM is overlapped with the gate G but thetwo are separated by the gate insulation layer GI and not in contactwith each other. In the present embodiment, an Ohmic contact layer OC isformed on the surface of the semiconductor pattern layer SM, but theinvention is not limited thereto. The semiconductor pattern layer SM canbe a single- or multi-layer structure and contains amorphous silicon,polysilicon, microcrystalline silicon, monocrystalline silicon, organicsemiconductor material, oxide semiconductor material (such as indiumzinc oxide, indium gallium zinc oxide, other suitable materials, or acombination thereof), other suitable materials, or the above mentionedmaterials with dopant, or a combination of the materials above.

The material of the Ohmic contact layer OC is, for instance, an N-typedoped semiconductor, and the forming method thereof includes, forinstance, depositing a semiconductor via a chemical vapor depositionmethod and performing N-type ion doping at the same time, but theinvention is not limited thereto. In other embodiments, the material ofthe Ohmic contact layer OC can also be a P-type doped semiconductor.

Referring to FIG. 1C, a second conductive layer M2 is formed on thesemiconductor pattern layer SM and the gate insulation layer GI. Thesecond conductive layer M2 covers the gate insulation layer GI, thesemiconductor pattern layer SM, the Ohmic contact layer OC, and thecapacitor electrode CE. The semiconductor pattern layer SM and the Ohmiccontact layer OC are located between the gate insulation layer GI andthe second conductive layer M2. In the present embodiment, the secondconductive layer M2 is, for instance, a Ti/Al/Ti metal structure formedby stacking a plurality of layers of titanium (Ti) and aluminum (Al),but the invention is not limited thereto. The second conductive layer M2can be a single-layer structure or multi-layer stacked compositestructure, and the material thereof is, for instance, a metal materialsuch as titanium, aluminum, molybdenum, silver, palladium (Pd), or analloy thereof. The material of the second conductive layer M2 can be thesame as or different from the material of the patterned first conductivelayer M1.

Referring to FIG. 1D, a photosensitive material layer PS and a first topelectrode material layer TE1 are deposited on the second conductivelayer M2 in order. The second conductive layer M2, the photosensitivematerial layer PS, and the first top electrode material layer TE1 aresuccessively deposited on the substrate SB. In the present embodiment,the material of the photosensitive material layer PS includessilicon-rich oxide such as a PIN material or PN material, but is notlimited thereto. According to other embodiments, the material of thephotosensitive material layer PS includes silicon-rich nitride,silicon-rich oxynitride, silicon-rich carbide, silicon-rich carbonoxide, hydrogenated silicon-rich oxide, hydrogenated silicon-richnitride, hydrogenated silicon-rich carbide, or a combination thereof.

Referring to FIG. 1E, a first patterned photoresist layer PR1 is formedon the first top electrode material layer TE1. In the presentembodiment, the first patterned photoresist layer PR1 is overlapped withthe capacitor electrode CE, but the invention is not limited thereto.

Referring to FIG. 1F, the first top electrode material layer TE1 ispatterned by using the first patterned photoresist layer PR1 as a maskto form a first top electrode TE1′. In the present embodiment, the firsttop electrode TE1′ is overlapped with the capacitor electrode CE, butthe invention is not limited thereto. In the present embodiment, thefirst top electrode TE1′ can be a transparent conductive material suchas metal oxide, such as indium tin oxide, indium zinc oxide, aluminumtin oxide, aluminum zinc oxide, indium gallium zinc oxide, othersuitable oxides, or a stacked layer of at least two of the above.

Referring to FIG. 1G, the first patterned photoresist layer PR1 isremoved.

Referring to FIG. 1H, the photosensitive material layer PS is patternedby using the first top electrode TE1′ as a mask to form a photosensitivelayer PS′. In the present embodiment, the photosensitive layer PS′ isoverlapped with the capacitor electrode CE, but the invention is notlimited thereto. In a preferred embodiment, the sizes of the verticalprojections of the photosensitive layer PS′ and the first top electrodeTE1′ on the substrate SB are substantially the same. It should bementioned that, when the photosensitive material layer PS is etched byusing the first top electrode TE1′ as a mask, lateral etching may occur,such that some lateral etching may occur to the resulting photosensitivelayer PS′ near the first top electrode TE1′ after etching. The materialof the photosensitive layer PS′ is the same as that of thephotosensitive material layer PS and is not repeated herein.

Referring to FIG. 1I, a second patterned photoresist layer PR2 is formedon the second conductive layer M2. The second patterned photoresistlayer PR2 has an opening OP corresponding to the semiconductor patternlayer SM to expose a portion of the second conductive layer M2.

Referring to FIG. 1J, the second conductive layer M2 is patterned byusing the second patterned photoresist layer PR2 as a mask to define apatterned electrode layer M2′ and a bottom electrode BE. The bottomelectrode BE is connected to the patterned electrode layer M2′. In thepresent embodiment, a portion of the Ohmic contact layer OC is alsoremoved to leave an Ohmic contact layer OC′.

The patterned electrode layer M2′ covers a portion of the semiconductorpattern layer SM. The patterned electrode layer M2′ includes a source S,a drain D, and a data line DL (shown in FIG. 2). In the presentembodiment, the source S and the drain D can be formed by etching usinga wet etchant, but the invention is not limited thereto. The wet etchantis, for instance, sulfuric acid, phosphoric acid, nitric acid, aceticacid, or a mixture of at least two of the above, aluminate etchingsolution, or other suitable etchants. The source S is electricallyconnected to the data line DL, the drain D is electrically connected tothe bottom electrode BE, and the source S and the drain D areelectrically connected to the semiconductor pattern layer SM.

The bottom electrode BE is overlapped with the capacitor electrode CEand the two are separated by the gate insulation layer GI and not incontact with each other. The bottom electrode BE, the photosensitivelayer PS′, and the first top electrode TE1′ are stacked on the substrateSB in order.

The bottom electrode BE formed by patterning the second conductive layerM2, the photosensitive layer PS′ formed by patterning the photosensitivematerial layer PS, and the first top electrode TE1′ formed by patterningthe first top electrode material layer TE1 are successively deposited onthe substrate SB. In other words, the bottom electrode BE, thephotosensitive material layer PS, and the first top electrode materiallayer TE1 are successively deposited on the substrate SB. For instance,after the second conductive layer M2 is deposited, the photosensitivematerial layer PS and the first top electrode material layer TE1 aredeposited at least on the bottom electrode BE in the second conductivelayer M2. The second conductive layer M2, the photosensitive materiallayer PS, and the first top electrode material layer TE1 aresuccessively deposited on the substrate SB. In some embodiments, thebottom electrode BE and the photosensitive layer PS′ have asubstantially flat interface therebetween. In some embodiments, asubstantially flat interface is located between the photosensitive layerPS′ and the first top electrode TE1′, and damage to the interfacebetween layers can be reduced via successive deposition such that theinterface between the layers is flatter. Therefore, the issue of poorimaging of the photosensitive element is solved, and display quality ofthe display device is increased.

In the present embodiment, a switch element T is, for instance, abottom-gate thin-film transistor including a gate G, a source S, a drainD, and a semiconductor pattern layer SM, but the invention is notlimited thereto. In other embodiments, the switch element T can also bea top-gate thin-film transistor or other suitable thin-film transistors.The switch element T is electrically connected to the bottom electrodeBE.

A data line DL and a scan line SL are intersected with each other (shownin FIG. 2), and the gate insulation layer GI is disposed between thedata line DL and the scan line SL. In an embodiment of the invention,the extending direction of the scan line SL is not parallel to theextending direction of the data line DL as an example. Preferably, theextending direction of the scan line SL and the extending direction ofthe data line DL are perpendicular to each other.

Referring to FIG. 1K, the second patterned photoresist layer PR2 isremoved.

Referring to FIG. 1L, an insulation layer IL is formed on the first topelectrode TE1′, and the insulation layer IL has an opening O1. Theinsulation layer IL covers the first top electrode TE1′, and the openingO1 exposes a portion of the first top electrode TE1′. The insulationlayer IL covers the photosensitive layer PS′ and the bottom electrodeBE. The insulation layer IL is omitted between the bottom electrode BEand the photosensitive layer PS′. The material of the insulation layerIL contains an inorganic material (such as: silicon oxide, siliconnitride, silicon oxynitride, other suitable materials, or stacked layersof at least two materials thereof), an organic material, other suitablematerials, or a combination thereof.

Referring to FIG. 1M, a second top electrode TE2 is formed on theinsulation layer IL to largely complete a photosensitive element 10. Aportion of the insulation layer IL is located between the first topelectrode TE1′ and the second top electrode TE2. The second topelectrode TE2 is electrically connected to the first top electrode TE1′via the opening O1. In the present embodiment, a thickness t2 of thesecond top electrode TE2 is greater than a thickness t1 of the first topelectrode TE1′. In the present embodiment, the photosensitive layer PS′is flat, and therefore the overlapping area between the bottom electrodeBE and the first top electrode TE1′ can be maximized to increase theeffective electric field between the two. In the present embodiment, thematerial of the second top electrode TE2 can be the same as or differentfrom that of the first top electrode TE1′, the second top electrode TE2can be a transparent conductive material, and the material is, forinstance, a metal oxide such as indium tin oxide, indium zinc oxide,aluminum tin oxide, aluminum zinc oxide, indium gallium zinc oxide,other suitable oxides, or a stacked layer of at least two of the above.

Referring to FIG. 1N, a light-shielding layer M3 is formed on the secondtop electrode TE2. The light-shielding layer M3 is overlapped with thegate G. The material of the light-shielding layer M3 can be a single- ormulti-layer stacked metal material (such as at least one selected fromthe group consisting of copper, molybdenum, titanium, aluminum,tungsten, silver, gold, and an alloy thereof), a resin material (such aspolyimide, acrylate, or other suitable resin materials), graphite, orother suitable materials.

Referring to FIG. 1O, a flat layer FL is formed on the second topelectrode TE2. The flat layer FL covers the second top electrode TE2. Inthe present embodiment, the material of the flat layer FL is an organicmaterial such as polyester (PET), polyolefin, polypropylene,polycarbonate, polyalkylene oxide, polyphenylene, polyether, polyketone,polyol, polyaldehyde, other suitable materials, or a combinationthereof, but the invention is not limited thereto. According to otherembodiments, the material of the flat layer FL can also be an inorganicmaterial (such as silicon oxide, silicon nitride, silicon oxynitride,other suitable materials, or a stacked layer of at least two of theabove materials), other suitable materials, or a combination thereof.

The thickness of the flat layer FL is greater than 2 μm and less than orequal to 25 μm. In a preferred embodiment, the thickness of the flatlayer FL is greater than 12 μm and less than or equal to 25 μm. In thepresent embodiment, an increase in the thickness of the flat layer FLcan increase the tolerance of the electronic element for electrostaticdischarge (ESD). In the present embodiment, when the thickness of theflat layer FL is greater than 25 μm, the photosensitive element is lessresponsive.

In the present embodiment, the dielectric strength of the flat layer isgreater than 200 MV/m. An increase in the dielectric strength of theflat layer can increase the tolerance of the electronic element for ESD.As a result, the life time of the electronic element can be increased.

Based on the above, via the successive deposition of the bottomelectrode BE, the photosensitive layer PS′, and the first top electrodeTE1′, damage to the interface between layers in the photosensitiveelement 10 can be reduced, and the issue of poor imaging of thephotosensitive element can be solved to increase the display quality ofthe display device.

FIG. 3 is a cross section of a photosensitive element according toanother embodiment of the invention. It should be mentioned here that,the embodiment of FIG. 3 adopts the reference numerals of theembodiments of FIGS. 1A to 1O and FIG. 2 and a portion of the contentsthereof, wherein the same or similar numerals are used to represent thesame or similar elements and descriptions of the same technical contentsare omitted. The omitted portions are as described in the aboveembodiments and are not repeated herein.

Referring to FIG. 3, in the present embodiment, the method of formingthe flat layer FL includes first forming a first organic flat materiallayer on the second top electrode TE2, curing the first organic flatmaterial layer to form a first organic flat layer FL1, forming a secondorganic flat material layer on the first organic flat layer FL1, andcuring the second organic flat material layer to form a second organicflat layer FL2. Due to there are two organic flat layers, the organicflat material of each coating can be thinner, and the material can bemore completely cured to avoid poor quality of the photosensitiveelement caused by incomplete curing. In other words, in the presentembodiment, the flat layer FL includes two organic flat layers, but isnot limited thereto. In other embodiments, the flat layer FL can includeone or more than two organic flat layers.

In the present embodiment, after the flat layer FL is formed, atransparent conductive layer ITO is formed on the flat layer FL. Thetransparent conductive layer ITO, for instance, completely covers theflat layer FL. The transparent conductive layer ITO is electricallyconnected to a ground voltage. The material of the transparentconductive layer ITO includes a metal oxide such as gallium zinc oxide,indium tin oxide, or indium zinc oxide.

In the present embodiment, a photosensitive element 20 further includesa backlight module 100. The backlight module 100 is located below thesubstrate SB. When a light L emitted by the backlight module 100 isirradiated on a test object OB located above the transparent conductivelayer ITO, the light L is reflected by the test object OB to thephotosensitive layer PS′. In an embodiment, the test object OB is, forinstance, a finger, and the photosensitive element 20 can detect a stateof a fingerprint on the finger.

Based on the above, via the successive deposition of the bottomelectrode BE, the photosensitive layer PS′, and the first top electrodeTE1′, damage to the interface between layers in the photosensitiveelement 20 can be reduced, and the issue of poor imaging of thephotosensitive element can be solved to increase the display quality ofthe display device.

FIG. 4 is a top view of a photosensitive element according to anotherembodiment of the invention. FIG. 5 is a cross section of aphotosensitive element shown according to section line B-B′ of FIG. 4.It should be mentioned here that, the embodiments of FIG. 4 and FIG. 5adopt the reference numerals of the embodiment of FIG. 3 and a portionof the contents thereof, wherein the same or similar numerals are usedto represent the same or similar elements and descriptions of the sametechnical contents are omitted. The omitted portions are described inthe previous embodiments and are not repeated in the followingembodiments.

The distinguishing feature of the embodiment of FIG. 5 from theembodiment of FIG. 3 is that the transparent conductive layer ITO isreplaced by a patterned wire layer CL.

Referring to FIG. 4 and FIG. 5, in a photosensitive element 30 of thepresent embodiment, a flat layer FL is formed on the second topelectrode TE2. Although only one flat layer is formed in the presentembodiment, the invention is not limited thereto. In other embodiments,the flat layer FL can be two or more layers.

After the flat layer FL is formed, the patterned wire layer CL is formedon the flat layer FL. The patterned wire layer CL is located on the flatlayer FL and overlapped with the switch element T. In the presentembodiment, the patterned wire layer CL is further overlapped with thescan line SL and the data line DL to prevent reduced aperture ratio. Thepatterned wire layer CL is electrically connected to a ground voltage.In the present embodiment, the patterned wire layer CL has the functionof antistatic, and can increase the tolerance of the electronic elementfor ESD. As a result, the life time of the electronic element can beincreased.

Based on the above, via the successive deposition of the bottomelectrode BE, the photosensitive layer PS′, and the first top electrodeTE1′, damage to the interface between layers in the photosensitiveelement can be reduced, and the issue of poor imaging of thephotosensitive element can be solved to increase the display quality ofthe display device. Moreover, when the photosensitive element 30 has thepatterned wire layer CL having antistatic function, the tolerance of theelectronic element for ESD can be increased.

Based on the above, in the photosensitive element and the manufacturingmethod thereof of the invention, via the successive deposition of thebottom electrode, the photosensitive material layer, and the first topelectrode material layer, damage to the interface between layers in thephotosensitive element can be reduced. As a result, the issue of poorimaging of the photosensitive element can be solved, and the displayquality of the display device can be increased. Moreover, via the flatlayer having a high dielectric strength or the patterned wire layerhaving antistatic function, the tolerance of the electronic element forESD can be increased, and the service life of the electronic element canbe increased.

Although the invention has been described with reference to the aboveembodiments, it will be apparent to one of ordinary skill in the artthat modifications to the described embodiments may be made withoutdeparting from the spirit of the invention. Accordingly, the scope ofthe invention is defined by the attached claims not by the abovedetailed descriptions.

What is claimed is:
 1. A photosensitive element, comprising: a bottomelectrode, a photosensitive layer, and a first top electrode stacked ona substrate in order, wherein a material of the photosensitive layercomprises a silicon-rich oxide, wherein the bottom electrode and thephotosensitive layer have a substantially flat interface therebetween;an insulation layer disposed on the first top electrode and covering thefirst top electrode, the photosensitive layer, and the bottom electrode,and the insulation layer has an opening; a second top electrodeelectrically connected to the first top electrode via the opening; and aswitch element electrically connected to the bottom electrode, wherein adrain of the switch element and the bottom electrode belong to a samelayer, wherein an entire bottom surface of the photosensitive layer isdirectly in contact with the bottom electrode, and at least a part of asidewall of the photosensitive layer is located between a bottom surfaceof the first top electrode and a top surface of the bottom electrode ina direction perpendicular to a top surface of the bottom electrodelayer, wherein the bottom electrode overlaps a capacitor electrode. 2.The photosensitive element of claim 1, wherein a thickness of the secondtop electrode is greater than a thickness of the first top electrode. 3.The photosensitive element of claim 1, wherein a portionof theinsulation layer is located between the first top electrode and thesecond top electrode.
 4. The photosensitive element of claim 1, whereinthe insulation layer is omitted between the bottom electrode and thephotosensitive layer.
 5. The photosensitive element of claim 1, furthercomprising: a flat layer covering the second top electrode.
 6. Thephotosensitive element of claim 5, further comprising: a patterned wirelayer located on the flat layer and overlapped with the switch element,wherein the patterned wire layer is electrically connected to a groundvoltage.
 7. The photosensitive element of claim 5, further comprising: atransparent conductive layer located on the flat layer and electricallyconnected to a ground voltage.
 8. The photosensitive element of claim 1,wherein the second top electrode covers at least a sidewall of the firsttop electrode.
 9. A photosensitive element, comprising: a bottomelectrode, a photosensitive layer, and a first top electrode stacked ona substrate in order, wherein a material of the photosensitive layercomprises a silicon-rich oxide, wherein the bottom electrode and thephotosensitive layer have a substantially flat interface therebetween;an insulation layer disposed on the first top electrode and covering thefirst top electrode, the photosensitive layer, and the bottom electrode,and the insulation layer has an opening; a second top electrodeelectrically connected to the first top electrode via the opening; and aswitch element electrically connected to the bottom electrode, wherein adrain of the switch element and the bottom electrode belong to a samelayer, wherein an entire bottom surface of the photosensitive layer isdirectly in contact with the bottom electrode, and at least a part of asidewall of the photosensitive layer is located between a bottom surfaceof the first top electrode and a top surface of the bottom electrode ina direction perpendicular to a top surface of the bottom electrodelayer, wherein the second top electrode overlaps the switch element. 10.The photosensitive element of claim 9, wherein the bottom electrodeoverlaps a capacitor electrode.
 11. A photosensitive element,comprising: a bottom electrode, a photosensitive layer, and a first topelectrode stacked on a substrate in order, wherein a material of thephotosensitive layer comprises a silicon-rich oxide, wherein the bottomelectrode and the photosensitive layer have a substantially flatinterface therebetween; an insulation layer disposed on the first topelectrode and covering the first top electrode, the photosensitivelayer, and the bottom electrode, and the insulation layer has anopening; a second top electrode electrically connected to the first topelectrode via the opening; and a switch element electrically connectedto the bottom electrode, wherein a drain of the switch element and thebottom electrode belong to a same layer, wherein an entire bottomsurface of the photosensitive layer is directly in contact with thebottom electrode, and at least a part of a sidewall of thephotosensitive layer is located between a bottom surface of the firsttop electrode and a top surface of the bottom electrode in a directionperpendicular to a top surface of the bottom electrode layer, whereinthe insulation layer directly contacts the first top electrode and asemiconductor pattern layer of the switch element.
 12. Thephotosensitive element of claim 11, wherein a thickness of the secondtop electrode is greater than a thickness of the first top electrode.13. The photosensitive element of claim 11, wherein a portion of theinsulation layer is located between the first top electrode and thesecond top electrode.
 14. The photosensitive element of claim 11,wherein the insulation layer is omitted between the bottom electrode andthe photosensitive layer.
 15. The photosensitive element of claim 11,further comprising: a flat layer covering the second top electrode. 16.The photosensitive element of claim 15, further comprising: a patternedwire layer located on the flat layer and overlapped with the switchelement, wherein the patterned wire layer is electrically connected to aground voltage.
 17. The photosensitive element of claim 15, furthercomprising: a transparent conductive layer located on the flat layer andelectrically connected to a ground voltage.
 18. The photosensitiveelement of claim 11, wherein the bottom electrode overlaps a capacitorelectrode.
 19. The photosensitive element of claim 11, wherein thesecond top electrode overlaps the switch element.
 20. The photosensitiveelement of claim 11, wherein the second top electrode covers at least asidewall of the first top electrode.